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Better fix for concurrency issue

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git-svn-id: https://zxing.googlecode.com/svn/trunk@1794 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2011-05-21 03:36:08 +00:00
parent c8166aec33
commit 87887ab18c
1 changed files with 29 additions and 24 deletions
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33
android/src/com/google/zxing/client/android/ViewfinderView.java
View file

@ -30,7 +30,6 @@ import android.view.View;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
/**
* This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial
@ -53,8 +52,8 @@ public final class ViewfinderView extends View {
private final int laserColor;
private final int resultPointColor;
private int scannerAlpha;
private final AtomicReference<List<ResultPoint>> possibleResultPoints;
private final AtomicReference<List<ResultPoint>> lastPossibleResultPoints;
private List<ResultPoint> possibleResultPoints;
private List<ResultPoint> lastPossibleResultPoints;
// This constructor is used when the class is built from an XML resource.
public ViewfinderView(Context context, AttributeSet attrs) {
@ -69,9 +68,8 @@ public final class ViewfinderView extends View {
laserColor = resources.getColor(R.color.viewfinder_laser);
resultPointColor = resources.getColor(R.color.possible_result_points);
scannerAlpha = 0;
possibleResultPoints = new AtomicReference<List<ResultPoint>>();
lastPossibleResultPoints = new AtomicReference<List<ResultPoint>>();
possibleResultPoints.set(new ArrayList<ResultPoint>(5));
possibleResultPoints = new ArrayList<ResultPoint>(5);
lastPossibleResultPoints = null;
}
@Override
@ -114,30 +112,34 @@ public final class ViewfinderView extends View {
float scaleX = frame.width() / (float) previewFrame.width();
float scaleY = frame.height() / (float) previewFrame.height();
List<ResultPoint> currentPossible = possibleResultPoints.get();
List<ResultPoint> currentLast = lastPossibleResultPoints.get();
List<ResultPoint> currentPossible = possibleResultPoints;
List<ResultPoint> currentLast = lastPossibleResultPoints;
if (currentPossible.isEmpty()) {
lastPossibleResultPoints.set(null);
lastPossibleResultPoints = null;
} else {
possibleResultPoints.set(new ArrayList<ResultPoint>(5));
lastPossibleResultPoints.set(currentPossible);
possibleResultPoints = new ArrayList<ResultPoint>(5);
lastPossibleResultPoints = currentPossible;
paint.setAlpha(CURRENT_POINT_OPACITY);
paint.setColor(resultPointColor);
synchronized (currentPossible) {
for (ResultPoint point : currentPossible) {
canvas.drawCircle(frame.left + (int) (point.getX() * scaleX),
frame.top + (int) (point.getY() * scaleY),
6.0f, paint);
}
}
}
if (currentLast != null) {
paint.setAlpha(CURRENT_POINT_OPACITY / 2);
paint.setColor(resultPointColor);
synchronized (currentLast) {
for (ResultPoint point : currentLast) {
canvas.drawCircle(frame.left + (int) (point.getX() * scaleX),
frame.top + (int) (point.getY() * scaleY),
3.0f, paint);
}
}
}
// Request another update at the animation interval, but only repaint the laser line,
// not the entire viewfinder mask.
@ -161,11 +163,14 @@ public final class ViewfinderView extends View {
}
public void addPossibleResultPoint(ResultPoint point) {
List<ResultPoint> points = possibleResultPoints.get();
List<ResultPoint> points = possibleResultPoints;
synchronized (point) {
points.add(point);
if (points.size() > MAX_RESULT_POINTS) {
int size = points.size();
if (size > MAX_RESULT_POINTS) {
// trim it
points.subList(0, points.size() - MAX_RESULT_POINTS / 2).clear();
points.subList(0, size - MAX_RESULT_POINTS / 2).clear();
}
}
}